Q: My 3-year-old son only sees his dad three days/two nights a week. I recently found out that his girlfriend stays over on the nights my son is there. Is this appropriate?

A: It sounds as if you are asking me this question based on moral grounds and if that is true, much to the dismay of many of my readers who believe the best way to maintain a relationship is to marry, a 3-year-old doesn’t understand if you are “married” or not — only if you are loving, nurturing, sensitive, kind, and very important, consistent.

If you are asking me if the girlfriend sleeping over is detrimental to your child based on something other than moral grounds, the answer is this: It is not detrimental if your ex and this woman are in a loving committed relationship and are planning a future together.

It is not detrimental if they follow the 10 rules of good ex-etiquette, the primary rule being, “Put the child first,” and together demonstrate positive interaction with this child. (The 10 rules of good ex-etiquette can be found on the Bonus Families website, www.bonusfamilies.com.)

It is not detrimental if they consult you about rules and discipline so you can support each other in the best interest of your son.

It IS detrimental if this is a “hit it and quit it” relationship where no one really cares either way if they will be seeing each other tomorrow. Kids need consistency and get attached to those we date, so introducing them to someone who is around now, but may be gone tomorrow, is not in a child’s best interest.

Here’s something important to remember: You can only control your four walls. Barring drugs, alcohol abuse or domestic violence, if you attempt to control dad and his love life, communication will break down and it could become difficult to talk to your child when he is with dad.

As much as dad’s lifestyle may not be your choice, the main concern is if the child is loved and safe. If this woman is sleeping over when your child is around, I would hope dad regards her as serious and if that is the case, that would be a signal for you as parents to talk.

Put boundaries in place that will allow you to respect each other’s privacy as well as successfully co-parent. And, meet the girlfriend! She’s with your child three days a week — or at least two nights. That’s close to one-third of your child’s life.

Dr. Jann Blackstone is the founder of Bonus Families, www.bonusfamilies.com. Reach her at:

drjannblackstonegmail.com